Do not change the default values set by device for all blank fields above. Restart Asus Zenfone 4 Max Plus ZC554KL.

For Asus Zenfone 4 Max Plus ZC554KL, when you type CTExcel APN settings, make sure you enter APN settings in correct case. For example, if you are entering CTExcel Internet APN settings
make sure you enter APN as tslpaygnet and not as TSLPAYGNET or Tslpaygnet.
If entering CTExcel MMS APN settings above to your Asus Zenfone 4 Max Plus ZC554KL, APN should be entered as tslmms and not as TSLMMS or Tslmms.